Jest, React and mocks

I use Facebook’s Jest to test my React applications. Yesterday, I ran a test to make sure that the changes I made to my Work component passed in my Portfolio React app. It did not! But as indicated in the iTerm2 console, it was not because of any errors in the Work component. It was because I am using a .pdf file in my About component, and Jest does not take kindly to it.

Apparently I hadn’t included .pdf! That was because I had added that asset much later, and didn’t think to add it to my jest configuration in package.json. That resulted in my test failing. I added pdf to the mix:

Then I ran npm run test in iTerm2 again. And guess what? My test passed!

So if you are using Jest to run tests in your React application, make sure that you mock out certain types of assets that would otherwise cause your tests to fail! I have included links to resources related to this topic at the end of the article.

Share this:

Like this:

Related

Maria Campbell

Founder, Inter-Global Media Network, Inc., where I focus on Front End Development. as well as a digital photographer, videographer, blogger, broadcaster, and graphic designer. Genesis Framework user. I got my start 8+ years ago teaching myself HTML/CSS and Wordpress Development because I couldn't find anyone who could create what I wanted. I have been working with open source software ever since. I am an open source software evangelist, and a "Women in Technology" evangelist. A creative professional myself, I find Web Development to be both practical and creative. I love to cook, travel, read mysteries, love everything French, the beach at sunrise, my three cats, and hope to revisit the city of San Francisco one day.

Reader Interactions

Comment Policy: Your words are your own, so be nice and helpful if you can. Please, only use your real name and limit the amount of links submitted in your comment. We accept clean XHTML in comments, but don't overdo it please. Comments are moderated, so spammy or malicious links will be removed.